A directory of Objective Type Questions covering all the Computer Science subjects. Here you can access and discuss Multiple choice questions and answers for various compitative exams and interviews.

101. A computer system supports 32 bit virtual address as well as 32 bit physical addresses. Since the virtual address space is of same size as that of physical address space, if we want to get rid of virtual memory, which one of the following is true ?
a. Efficient implementation of multiuser support is no longer possible.
b. The processor cache can be made more efficient.
c. Hardware support for memory management is not needed.
d. CPU scheduling can be made more efficient.
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Answer: (c).Hardware support for memory management is not needed.

102. If an instruction takes ‘i’ microseconds and a page fault takes an additional ‘j’ microseconds. The effective instruction time, if on the average a page fault occurs every k instructions, is
a. i + j/k
b. i + j * k
c. (i + j)/k
d. (i + j) * k
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Answer: (a).i + j/k

103. Consider the methods used by processes P1 and P2 for accessing their critical sections. The initial values of shared Boolean variables S1 and S2 are randomly assigned,

P1                                         P2
while (S1 = = S2);             while (S1 = = S2);
critical section                  critical section
S1 = S2;                              S1 = S2;

Which one of the following statements describes the properties achieved ?
a. Mutual exclusion but not progress
b. Progress but not mutual exclusion
c. Neither mutual exclusion nor progress
d. Both mutual exclusion and progress
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Answer: (c).Neither mutual exclusion nor progress

104. On a disk with 1000 cylinders (0 to 999) find the number of tracks, the disk arm must move to satisfy all the requests in the disk queue. Assume the last request service was at track 345 and the head is moving toward track 0. The queue in FIFO order contains requests for the following tracks :
123, 874, 692, 475, 105, 376
(Assume SCAN algorithm)
a. 2013
b. 1219
c. 1967
d. 1507
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Answer: (b).1219

105. Dijkestra banking algorithm in an operating system, solves the problem of
a. deadlock avoidance
b. deadlock recovery
c. mutual exclusion
d. context switching
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Answer: (a).deadlock avoidance

106. The multiuser operating system, 20 requests are made to use a particular resource per hour, on an average the probability that no request are made in 45 minutes is
a. e^-15
b. e^-5
c. 1 – e^-5
d. 1 – e^-10
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Answer: (a).e^-15

107. The maximum amount of information that is available in one portion of the disk access arm for a removal disk pack (without further movement of the arm with multiple heads)
a. a plate of data
b. a cylinder of data
c. a track of data
d. a block of data
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Answer: (b).a cylinder of data

108. A file organization component VSAM file is
a. Relative records data set
b. Keyed sequential data set
c. Entry sequential data set
d. All of the above
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Answer: (d).All of the above

109. A relationship between processes such that each has some part (critical section) which must not be executed while the critical section of another is being executed, is known as
a. Semaphore
b. Mutual exclusion
c. Multiprogramming
d. Message passing
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Answer: (b).Mutual exclusion

110. How many states can a process be in ?
a. 3
b. 4
c. 2
d. 5
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Answer: (d).5